Distribution of API on Stent

Addressing Pharmaceutical Issues

Through Microscopy: A Case Study


THE PROBLEM: Pharmaceutical manufacturers are always concerned with the distributions of the active pharmaceutical ingredient (API) and excipients on a medical device or in a drug. Knowing the distribution helps scientists understand the efficacy of the drug and to fine tune the manufacturing process. In this case, MVA Scientific Consultants was asked to map the distribution of API on stent, polymer and copolymer on the surface of the arterial stent.


THE ANALYSIS: MVA used a high resolution confocal Raman microscope to perform XZ mapping of the stent. This technique is nondestructive, therefore, the samples can be returned to the manufacturer. Several maps were produced to make sure the results were representative.


Drug coated stent

THE IMAGE: The top image is an arterial stent. The bottom image shows a depth distribution map of the different components along the stent:

• Blue – polymer

• Red – copolymer mixture

• Yellow – API


Distribution of API on coated stent

THE OUTCOME: MVA’s results showed the manufacturer that the coatings were evenly layered, and the API was distributed uniformly throughout the polymers. In addition, they showed that the stent coating thickness was within the manufacturing requirement.